1. Technical Field
The present invention relates to a catalyst for treating exhaust gases that contain nitrogen monoxide, carbon monoxide and volatile organic compounds, a method for producing the same, and a method for treating exhaust gases.
2. Background Art
Exhaust gases emitted from various industrial products, such as cars and aircraft, and from various factories contain NOx (nitrogen oxides), CO (carbon monoxide) or unburned hydrocarbons. To treat these inclusions, catalysts for treating exhaust gases have been used. For example, a NMHC (Non-Methane Unburned Hydrocarbons) oxidation catalyst that includes: an alumina carrier; and Pt (platinum), as an active component, supported on the alumina carrier is described in Japanese Patent Laid-Open No. 10-309462.
The patent publication describes a method of producing the oxidation catalyst, which includes the steps of: supporting alumina on a substrate having a honeycomb structure by wash-coating; and dipping the substrate having alumina supported on its surface in an aqueous solution of dinitro diammine platinum so that Pt is supported on the alumina.
In this method, however, to enhance the oxidation power of the catalyst, it is necessary to increase the amount of the active component, such as Pt. This means a large amount of an expensive precious metal, such as Pt, has to be used, causing the problem of increasing the production cost.